MESIAL TEMPORAL SCLEROSIS - PATHOGENESIS AND SIGNIFICANCE

Mesial temporal sclerosis (MTS) is a common pathologic finding in pati ents with temporal lobe epilepsy, Rarely MTS can be detected in childr en during the first decade of life, but is not commonly found until ad olescence, Although the etiology of MTS remains controversial, there i s now a considerable amount of evidence demonstrating that MTS is both a result and a cause of seizures, Clinical studies suggest that prolo nged seizures or complicated febrile seizures may result in MTS, A var iety of epileptogenic agents administered to adult animals have result ed in MTS and spontaneous recurrent seizures, The mechanism of the les ions is due to excessive excitability secondary to release of excitato ry amino acids, primarily glutamate, Glutamate, acting at a number of subreceptors on the postsynaptic membrane, leads to prolonged depolari zation of neurons and results in the entry of cytotoxic amounts of cal cium, Interestingly, the same agents that produce MTS in adult animals do not produce MTS in immature animals, Clinical and experimental evi dence suggests that although prolonged seizures or complicated febrile seizures can place a child at risk for MTS, a period of time is requi red for the lesions to develop fully.